Otto schifferdecker



Patented Mar. 27, i923'.

UNITED STATES OTTO soHrrERDnoKnR, or wenns, GERMANY.

GRINDING DISK.

Application filed March 31 To all whom t may concern Be it known that l,OTTO SortierunnnoKEn, a citizen of the German Republic, residing atlVOims, Germany, have invented certain new and use-ful Improvements inGrinding Disks (for which l have filed an application in GermanyDecember 2, l9l3, and in Great Britain June l5, 1911i), of which thefollowing is a specification.

rThis invention relates to improvements in grinding disks and moreespecially to those used in the colour industry for grinding oilcolours. In such grinding mills, one of the grinding disks, usually theupper, is provided with a stationary feed hopper whilst the lower diskrotates co-axially with the fixed upper disk. T his arrangement causesgrooves or ridges to be formed on the grinding faces or edges and theseridges interfere with the ethcient grinding and prevent the free egressof the ground colour. This reduces the output of the mill. When theworkingis carried on for along timeI the two disks get interlocked theone with the other so that the material t-obe ground. cannot pass anymore, the grinding disks having to be rearranged.

The object of the invention is to avoid these inconveniences and toimprove besides the efficiency of the grinding.

According to this invention the grinding mill is provided with stones orgrinding disks which mutually overlap at opposite sides on theirbounding edges. In this way each disk, when rotating, is able toprotrude with part of its grinding surface over the circumference of theother disk at all points and thus eliectually prevents the formation ofgrooves as the two disks mutually grind one another into flat surfaces.

In order that the invention may be clearly understood, l shall proceedto describe the same with reference to the form of construction shown byway of example in the accompanying drawings, wherein Fig. l shows twodisks of a grinding mill in cross section together with the necessaryparts of the mill.

Fig. 2 is a plan of the disks with adjacent parts omitted.

In carrying the invention into effect according to the form shown thetwo rings 0 and p are arranged the one above the other and the upperring o is fixed whilst the lower ring p rotates. The ring o is cementedby cement e to the cementing disk /L Serial No. 457,548.

upon which the hopper g is screwed. The lower rotating ring p is mountedon a cementing disk t' carried by a shaft 7c, to which it is keyed orfixed so as to rotate with the said shaft. The central hollow of thedisk p is filled up with cement f. The grinding rings o, p may be madeof porcelain, iron, or a hard casting, a hard stone or any othersuitable material.

According to this invention the tworings o, p are of oval shape, beingbounded by elliptical lines p', 0 or of a similar ligure. Both ellipsesare congruent as regards their cio-operating faces. lt is evident thatowing to this shape two overlapping disks are formed. The crescentshaped parts p2, p3 and 02` 03 represent the inner and outer overlappingparts of the two grinding rings which are formed when said rings arerotating. When the mill is in operation an alternating overlapping ofthe two disks takes place in such a manner that the lower rotating diskp overlaps the upper ring 0, externally at m, and internally at i, y. Inthis way an automatic and mutual Orinding of the faces is ensured.Further the internal overlap at y, y draws away a portion of theunground colour from the hopper m and feeds it between the acting faces,said colour being thoroughly ground between the disks and ejected undercentrifugal action at the outer overlaps x. In this way it is possibleto d-o-uble the output of the mill with oval grinding disks as comparedwith concentric grinding disks, as well as regards the quantity as thelquality of the ground material.

Overlapping disks might be obtained by other means. Thus circular disksset eccentrically might be used to produce the same result or the axisaround which the disks rotate could be made movable in a closed curve orthe disks, when arranged with moving axis of rotation, could be made torotate simultaneously around their own axles. In every case theoverlapping feature is the necessity by means of which the mutualgrinding of the faces right up to their edges is obtained.

An improved mill for grinding colours and the like comprising incombination two grinding disks of which one is fixed and the other.rotatable, `two grinding rings each connected with one of said grindingdisks and being each of ova-l shape internally and diameter of the othergrinding rin E externally so that at two opposite points the innerandouter-diameter of the one grinding'ring is greater than thecorresponding g, the innerand outer-diameter of the last mentionedgrinding disk being greater at two opposite points situatedperpendieuiarly to the opposite points of the rst mentioned grindingring, and means for mounting and means for driving the grinding disks or10 grinding rings. In testimony whereof I affix my signature in presenceof two witnesses.

OTTO SLCHIFFERDECKEH.

VVitnesSes FRITZ BERG, KARL KLING.

